Patent GB-404106-A (GB)
Title: Improvements in or relating to electric signalling systems
IPC: H04Q9/04
Filed: 1932-10-13
Abstract: 404,106. Electric signalling systems. DEAN, W. H., 18, Cleveland Avenue, Darling- ton. Oct. 13, 1932, Nos. 28613/32 and 15609/33. [Class 40 (i).] In an electric signalling system of the kind wherein the position of a transmitting member is indicated at the receiver stroboscopically by flashing a lamp at predetermined points in a time period determined by synchronous motors, the lamp is supplied through a rectifier, from the mains that supply the synchronous motors. In the arrangement shown in Fig. 1 for indicating the position of arm H, synchronous motors A, a drive arms D, d the former of which is adapted to close the circuit of a neon lamp n, at a point in the cycle of revolution determined by the position of arm H and the latter carries or forms a reflector so that it is rendered visible in a position corresponding to that of the arm G. The lamp is supplied from the mains through a rectifier q. To facilitate the indication of synchronous operation fixed contacts S, s are provided and the circuit of the lamp n is closed over the switch M in its test position, only provided the contacts S, s are closed simultaneously. Instead of using a single lamp for indicating both synchronism and the positions of the arm G, independent lamps may be provided. Moreover instead of a test lamp, a slow release relay may be provided in the test circuit, the arrangement being such that during synchronous operation the relay is maintained operated to prepare the signal lamp circuit, but in the event of out-of-synchronous working, the relay is released to cut out the signal lamp. In a modification wherein a common lamp is used for both indications, the contact s is dispensed with and a resistance is connected in series with the contact S which is connected in parallel with arm H. The main signals and the synchronism indications are distinguished at the receiver by different strengths of illumination. Instead of using a stationary lamp n, the lamp may be mounted on the arm d. Moreover the system may be provided with similar apparatus at both stations to facilitate two-way signalling. In a modified form of transmitter, a light-sensitive cell may be enclosed within a continuously rotated screen and a second screen adapted to be adjusted in accordance with the signals to be transmitted. Both screens are provided with slits that allow illumination of the cell and the transmission of an impulse to the receiver at a point in the cycle corresponding to the position of the second screen. Synchronism indications also may be transmitted by illuminating the cell with a different quantity of light. In modified forms of receiver, the neon lamp may illuminate a rotary translucent screen bearing indications viewed through a slit in an outer screen or the lamp may be enclosed within a rotary drum having a slit and being adapted to project a beam of light on to a scale provided on the inside of a conical member. Instead of the rotary drum a non-rotary lens may project a beam of light on to a photographic recorder of the revolving drum type. Indications of the positions of a plurality of arms H may be transmitted simultaneously.